1. Technical Field
Illustrative embodiments described in this patent specification generally relate to an image forming apparatus, and more particularly to an image forming apparatus including an image reading unit, an image forming unit employing one or both of an inkjet recording system and an electrophotographic system, and at least upper and lower sheet roll supporters to support rolls of recording media sheets.
2. Description of the Related Art
An image forming apparatus is known that includes an image reading unit that reads an image of a document, an image forming unit that forms the image on a recording medium such as a sheet of paper, and at least upper and lower sheet roll supporters provided one above the other to respectively support sheet rolls constituted as one long continuous sheet wound around a core. The image reading unit, the image forming unit, and the upper and lower sheet roll supporters are provided, in that order, from the top to the bottom of the image forming apparatus, and each of the upper and lower sheet roll supporters supports the sheet roll such that the sheet is fed from the sheet roll. Examples of image forming apparatuses using the sheet roll to form images on the sheet fed from the sheet roll include large-scale copiers, printers, plotters, inkjet recording devices, and so forth, which are mainly used for drawing figures.
One example of the image reading unit included in the above-described image forming apparatus has a document conveyance path, a reading part, a circuit substrate that controls the reading part, and an upper structure openably closable to expose the document conveyance path. The upper structure is opened so that a user can handle the reading part and the circuit substrate independently from one side of the image forming apparatus. The image forming unit and a sheet feeder are further included in the image forming apparatus. More specifically, the image reading device, the image forming unit, and the sheet feeder are provided, in that order, from the top to the bottom of the image forming apparatus. The sheet feeder includes upper and lower pull-out-type sheet roll trays provided one above the other, which are pulled out from a main body of the image forming apparatus to set a sheet roll therein or to fix a sheet jam.
Another example of an image forming apparatus includes an image forming unit and a sheet feeder having upper and lower sheet roll supporters provided one above the other, in that order, from the top to the bottom of the image forming apparatus. The sheet feeder includes a sheet roll container for replacing a sheet roll, a sheet puller that unwinds the sheet roll contained in the sheet roll container, a cutter that cuts the sheet unwound by the sheet puller, a sheet conveyance unit to convey the sheet cut by the cutter to a predetermined conveyance path, and a pull-out-type housing including the sheet roll container, the sheet puller, the cutter, and the sheet conveyance unit. A concave sheet roll support member is provided in an upper portion of the housing so that the sheet roll can be temporarily placed on the sheet roll support member when the housing is pulled out from the image forming apparatus.
In yet another approach, a roll feeder detachably attachable to the image forming apparatus includes a supporter provided in a lower portion of the image forming apparatus to support a roll of a recording medium.
In an image forming apparatus in which the image reading unit is provided at the top thereof and the image forming unit and at least the upper and lower sheet roll supporters are provided below the image reading unit, in that order, from the top to the bottom of the image forming apparatus, it is preferable that a height of the image forming apparatus be, for example, not greater than 1,000 mm so that a user can easily access the image reading unit to set a document to be read thereupon.
The sheet feeder or the roll feeder is generally provided on a front side at the bottom of the image forming apparatus, so that a height of the image forming apparatus is reduced and the user can easily supply sheets or fix sheet jams from the front side of the image forming apparatus. Such a configuration is called a front operation system or a front loading system, and as a result, the user can easily operate an operation panel or a document stand provided on the front side at the top of the image forming apparatus, thereby providing the user-friendly configuration.
Multiple sheet rolls are often used and stored in these image forming apparatuses, which typically are very wide. In such an image forming apparatus, the sheet rolls are set one above the other in a vertical direction when the pull-out-type housing usually having a complex configuration is not provided in the image forming apparatus. Although depending on the type, width, and length of the sheet wound around the core, a weight of the sheet roll often exceeds 10 kg. Consequently, it is not easy to set such heavy sheet rolls one above the other in the image forming apparatus without the pull-out-type housing compared to loading the typically distributed stacks of sheets cut in a predetermined length. In addition, because a roll of glossy sheet is usually very costly, more care is needed to set the roll of glossy sheet to prevent damage thereto.
In an effort to overcome the above-described disadvantage, some image forming apparatuses, especially image forming apparatuses in which only one sheet roll is set, have a configuration in which the sheet roll supporter is provided in an upper portion of the image forming apparatuses. However, with the sheet rolls weighing in excess of 10 kg, it is difficult for users in general and female users in particular to lift such loads to the required chest-height level.